Transmitter devices having bridge structures

ABSTRACT

The present disclosure relates to optical systems and methods for their manufacture. An example system includes a first substrate that has at least one bridge structure. The bridge structure has a first surface with one or more light-emitter devices disposed on it. The system also includes a second substrate that has a mounting surface that defines a reference plane. The second substrate includes a structure and an optical spacer on the mounting surface. The first and second substrates are coupled together such that the first surface of the first substrate faces the second substrate at an angle with respect to the reference plane. The system also includes at least one spacer coupled to the mounting surface. The at least one spacer is in physical contact with the one or more light-emitter devices.

BACKGROUND

Achieving and maintaining proper alignment between optical components ina complex optical system can represent a formidable manufacturingchallenge. For example, some optical systems include parts that shouldbe arranged according to placement tolerances that can be 50 microns, 10microns, or even less.

SUMMARY

In a first aspect, an optical system is provided. The optical systemincludes a first substrate having at least one bridge structure. Thebridge structure includes a first surface. One or more light-emitterdevices are disposed on the first surface. The optical system alsoincludes a second substrate. The second substrate has a mounting surfacethat defines a reference plane. The second substrate includes astructure and an optical spacer on the mounting surface. The firstsubstrate and the second substrate are coupled together such that afirst portion of the first substrate is coupled to the optical spacer onthe mounting surface of the second substrate and the first surface ofthe first substrate faces the mounting surface of the second substrateat an angle with respect to the reference plane. The optical system yetfurther includes at least one spacer coupled to the mounting surface.The at least one spacer is in physical contact with the one or morelight-emitter devices.

In a second aspect, a method of manufacturing an optical system isprovided. The method includes forming at least one bridge structure in afirst substrate. The bridge structure comprises a first surface. Themethod also includes attaching one or more light-emitter devices to thefirst surface of the bridge structure. The method additionally includesproviding a second substrate. The second substrate has a mountingsurface that defines a reference plane. The method yet further includesforming a structure and an optical spacer on the mounting surface of thesecond substrate. The method also includes coupling at least one spacerto the mounting surface of the second substrate. The method additionallyincludes coupling the first and second substrates together such that afirst portion of the first substrate is coupled to the mounting surfaceof the second substrate and a second portion of the first substrate iscoupled to the optical spacer formed on the mounting surface of thesecond substrate and the first surface of the first substrate faces themounting surface of the second substrate at an angle with respect to thereference plane. The at least one spacer is in physical contact with theone or more light-emitter devices.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 illustrates an optical system, according to an exampleembodiment.

FIG. 2A illustrates a portion of an optical system, according to anexample embodiment.

FIG. 2B illustrates a portion of an optical system, according to anexample embodiment.

FIG. 2C illustrates a portion of an optical system, according to anexample embodiment.

FIG. 2D illustrates an optical system, according to an exampleembodiment.

FIG. 3A illustrates a step of a method of manufacture, according to anexample embodiment.

FIG. 3B illustrates a step of a method of manufacture, according to anexample embodiment.

FIG. 3C illustrates a step of a method of manufacture, according to anexample embodiment.

FIG. 3D illustrates a step of a method of manufacture, according to anexample embodiment.

FIG. 3E illustrates a step of a method of manufacture, according to anexample embodiment.

FIG. 3F illustrates a step of a method of manufacture, according to anexample embodiment.

FIG. 3G illustrates a step of a method of manufacture, according to anexample embodiment.

FIG. 4 illustrates a method, according to an example embodiment.

DETAILED DESCRIPTION

Example methods, devices, and systems are described herein. It should beunderstood that the words “example” and “exemplary” are used herein tomean “serving as an example, instance, or illustration.” Any embodimentor feature described herein as being an “example” or “exemplary” is notnecessarily to be construed as preferred or advantageous over otherembodiments or features. Other embodiments can be utilized, and otherchanges can be made, without departing from the scope of the subjectmatter presented herein.

Thus, the example embodiments described herein are not meant to belimiting. Aspects of the present disclosure, as generally describedherein, and illustrated in the figures, can be arranged, substituted,combined, separated, and designed in a wide variety of differentconfigurations, all of which are contemplated herein.

Further, unless context suggests otherwise, the features illustrated ineach of the figures may be used in combination with one another. Thus,the figures should be generally viewed as component aspects of one ormore overall embodiments, with the understanding that not allillustrated features are necessary for each embodiment.

I. Overview

The present disclosure provides systems and methods for opticaltransmitter devices that incorporate a bridge structure. In someexamples, two light-emitter devices (e.g., laser diodes) could bearranged along a surface of the bridge structure, which could beprovided as a portion of a first substrate. Respective top surfaces ofthe light-emitter devices (opposite the surfaces of the light-emitterdevices that are coupled to the bridge structure) could be in physicalcontact with a spacer. The spacer could exert a contact pressure on thelight-emitter devices. In some embodiments, the spacer could be attachedto a second substrate that includes a cylindrical lens and light guidemanifold (e.g., a waveguide or a light pipe).

In some embodiments, the disclosed bridge structures can flex when incontact with the spacer so as to beneficially provide more reliablealignment of the light-emitter devices with the correspondingcylindrical lens and optical waveguide elements on the second substrate.By placing two light-emitter devices on the bridge structure, bothlight-emitter devices can be aligned with the cylindrical lens at thesame time. Furthermore, height differences between the two light-emitterdevices can be compensated or accommodated by a torsional bending of thebridge structure. Furthermore, variations in bonding material thicknessbetween the first substrate and the respective light-emitter devices canbe mitigated with such bending.

In some example embodiments, the bridge structures could be 5 mm long by1 mm wide. However, other lengths and widths are possible. In addition,the aspect ratio (length/width) could be adjusted based on a desiredspring constant of the bridge structure and/or an actual or anticipatedheight variation between the light-emitter devices on the firstsubstrate.

Yet further, systems and methods described herein may provide somedegree of vibration isolation due to the spring force of the bridgestructure. Namely, vibrations induced in one or both of the firstsubstrate or second substrate could be at least partially damped by thebridge structure.

In some examples, the bridge structure and/or the first substrate couldbe formed from printed circuit board or flexible printed circuit boardmaterial. In some embodiments, the first substrate could beapproximately 200 microns thick. However, other materials arecontemplated and possible. The bridge structures could be formed using aphotolithography mask process followed by an anisotropic or isotropicetch process. In an example embodiment, the bridge structures could belaser cut or computer numerical control (CNC) milled from bulk substratematerials. Other additive or subtractive semiconductor/packagingmanufacturing methods are contemplated herein.

In some embodiments, both light-emitter devices could be controlled by asingle GaNFET driver circuit. Namely, the light-emitter devices could beconnected in a series or parallel arrangement in the driver circuit andcould be fired simultaneously and/or separately when the opticaltransmitter device is in operation. In such scenarios, at least aportion of the driver circuit could be incorporated on the bridgestructure.

While a pair of light-emitter devices and a corresponding single bridgestructure is described above, it will be understood that a plurality ofbridge structures is contemplated herein. Thus, an example embodimentcould include 10 or more bridge structures corresponding to 20 or morelight-emitter devices. In some examples, light emission fromlight-emitter devices located on respective bridge structures could beindividually controlled.

Other aspects, embodiments, and implementations will become apparent tothose of ordinary skill in the art by reading the following detaileddescription, with reference where appropriate to the accompanyingdrawings.

II. Example Systems

FIG. 1 illustrates an optical system 100, according to an exampleembodiment. Optical system 100 could be utilized in various compactLIDAR systems. Such LIDAR systems may be configured to provideinformation (e.g., point cloud data) about one or more objects (e.g.,distance, shape, etc.) in a given environment. In an example embodiment,the LIDAR system could provide point cloud information, objectinformation, mapping information, or other information to a vehicle. Thevehicle could be a semi- or fully-automated vehicle. For instance, thevehicle could be a self-driving car, an autonomous drone aircraft, anautonomous truck, or an autonomous robot. Other types of vehicles andLIDAR systems are contemplated herein.

The optical system 100 includes a first substrate 110. In some examples,the first substrate 110 could be approximately 200 microns thick.However, other thicknesses are possible and contemplated. In someembodiments, the first substrate 110 is a printed circuit board (PCB).In some other embodiments, the first substrate 110 could include asemiconductor substrate material such as silicon, gallium arsenide, orthe like. In some embodiments, the first substrate 110 could include asilicon-on-insulator (SOI) material or aluminum nitride. Alternatively,the first substrate 110 could be formed from a variety of other solidand/or flexible materials, each of which is contemplated in the presentdisclosure.

The first substrate 110 includes at least one bridge structure 102. Thebridge structure 102 includes a first surface 112. In some embodiments,the bridge structure 102 is defined by at least one cutout. The at leastone cutout could include an opening in the first substrate 110. The atleast one cutout could be formed by laser cutting or mechanical routing.Additionally or alternatively, the at least one cutout could be formedusing a lithographically-defined wet or dry etch process. In suchembodiments, the bridge structure 102 could be defined by two cutouts.In such scenarios, the bridge structure 102 could include an elongatemember 113 that extends between a first support end 116, and a secondsupport end 118. In some embodiments, the optical system 100 couldinclude a plurality of bridge structures 102 defined by a plurality ofcutouts.

One or more light-emitter devices 120 are disposed on the first surface112. The light-emitter devices 120 could be configured to provide lightpulses in infrared wavelengths (e.g., 905 nm). Other wavelengths andwavelength ranges are possible and contemplated. The light-emitterdevices 120 could each include one or more laser bars or another type oflight-emitting structure. In some embodiments, a driver circuit and/orcontrol circuitry (e.g., pulser circuits) for the light-emitter devices120 could also be disposed along the first surface 112 of the firstsubstrate 110. In other embodiments, the control circuitry could belocated elsewhere.

The optical system 100 also includes a second substrate 130 that has amounting surface 132 that defines a reference plane. The secondsubstrate 130 includes a structure 136 and an optical spacer 137 on themounting surface 132. In some cases, the structure 136 may be formedfrom a polymeric material, such as photoresist. For example, thepolymeric material may include SU-8 polymer, Kloe K-CL negativephotoresist, Dow PHOTOPOSIT negative photoresist, or JSR negative toneTHB photoresist. It will be understood that the structure 136 may beformed from other polymeric photo-patternable materials. The structure136 could be a photo-patterned material layer that is 400 microns thick.However, the structure 136 could be a different thickness.

In some embodiments, the structure 136 on the mounting surface 132 couldinclude an optical waveguide. For example, the optical waveguide couldbe configured to efficiently guide light along a propagation direction.For example, the structure 136 may be configured to couple light emittedfrom the plurality of light-emitter devices 120. At least a portion ofsuch light may be guided within at least a portion of the structure 136via total internal reflection and/or evanescent optical coupling. Insome embodiments, the structure 136 may include one or more reflectivesurfaces configured to direct light normal to the propagation direction.In such a scenario, at least a portion of the light may be coupled outof the structure 136 via a mirrored facet.

In some embodiments, the optical spacer 137 could be provided to improveoptical isolation between the structure 136 and the first substrate 110and/or to preserve the light guiding properties of the structure 136.For instance, in some scenarios, the optical spacer 137 could include apartially-etched stainless steel spacer that forms a “tunnel” or air gaparound the structure 136. In other words, such an optical spacer 137could be directly “sandwiched” between the first substrate 110 and thesecond substrate 130 in the region of the structure 136. That is, air—oranother material with a low refractive index with respect to that of thestructure 136—could surround at least a portion of the structure 136. Insuch scenarios, the structure 136 need not be directly coupled to thefirst substrate 110, but rather could be indirectly coupled to the firstsubstrate 110 by way of the optical spacer 137.

Put another way, in some embodiments, the optical spacer 137 may providea “scaffolding” around the structure 136 so as to prevent the firstsubstrate 110 from physically touching the structure 136. The opticalspacer 137 could be formed from copper, stainless steel, or anickel-cobalt ferrous alloy such as Kovar. Additionally oralternatively, the material of the optical spacer 137 could be selectedbased on its coefficient of thermal expansion (CTE). Specifically, theoptical spacer 137 could be formed from a material that has a CTEsimilar (e.g., within 10% or 1%) to that of the second substrate 130.

The first substrate 110 and the second substrate 130 are coupledtogether such that a first portion of the first substrate 110 (e.g., thefirst support end 116 of the bridge structure 102) is coupled to theoptical spacer 137 on the mounting surface 132 of the second substrate130 and the first surface 112 of the first substrate 110 faces themounting surface 132 of the second substrate 130 at an angle withrespect to the reference plane.

The optical system 100 additionally includes at least one spacer 140coupled to the mounting surface 132. The at least one spacer 140 is inphysical contact with the one or more light-emitter devices 120.

In some embodiments, the first support end 116 and the second supportend 118 of the bridge structure 102 define a plane. In such a scenario,the elongate member 113 of the bridge structure 102 is deformable withrespect to the plane.

Additionally or alternatively, the bridge structure 102 could include alongitudinal axis. In such scenarios, the bridge structure 102 could beconfigured to bend according to a transverse mode with respect to thelongitudinal axis.

Furthermore, the bridge structure 102 could include a longitudinal axis.In such example embodiments, the bridge structure 102 could beconfigured to bend according to a torsional mode with respect to thelongitudinal axis. Within the context of this disclosure, such torsionalbending may be important to provide self-correcting aspects of theoptical system 100 in view of part tolerances, and othersize/shape/alignment non-uniformities.

In some embodiments, the at least one spacer 140 could be an opticalfiber spacer. That is, the spacer 140 could be formed from an opticalfiber. In some embodiments, the at least one spacer 140 could becylindrical with a diameter between 40-60 microns. However, otherdiameters or shapes for the at least one spacer 140 are possible andcontemplated. In some embodiments, the at least one spacer 140 could becoupled to the mounting surface 132 with epoxy or another type ofadhesive. Additionally or alternatively, the at least one spacer 140could be disposed between at least one pair of three-dimensionalalignment structures (e.g., three-dimensional alignment structures 142,as described elsewhere herein). The at least one pair ofthree-dimensional alignment structures could be configured to secure theat least one spacer 140 from moving away to a predetermined location.

In example embodiments, the optical system 100 could include at leastone cylindrical lens 150 coupled to the mounting surface 132. In suchscenarios, the one or more light-emitter devices 120 could be arrangedto emit light towards the at least one cylindrical lens 150. In someembodiments, the at least one cylindrical lens 150 could include anoptical fiber lens. Furthermore, the optical fiber lens could have aradius greater than that of the optical fiber spacer.

In some embodiments, the at least one cylindrical lens 150 could becoupled to the mounting surface 132 with epoxy or another type ofadhesive. Additionally or alternatively, the at least one cylindricallens 150 could be disposed between at least one pair ofthree-dimensional alignment structures (e.g., three-dimensionalalignment structures 152, as described elsewhere herein). The at leastone pair of three-dimensional alignment structures could be configuredto secure the at least one cylindrical lens 150 to a predeterminedlocation. In an example embodiment, the cylindrical lens 150 could beutilized to focus, defocus, direct, and/or otherwise couple the emittedlight into the structure 136. In some embodiments, the cylindrical lens150 could be approximately 100-200 microns in diameter. However, otherdiameters are possible and contemplated. In addition, lenses that are inother shapes could be used instead of, or in addition to, the at leastone cylindrical lens 150.

As described above, the at least one spacer 140 and/or the at least onecylindrical lens 150 could include respective optical fibers. However,in other embodiments, the at least one spacer 140 and/or the at leastone cylindrical lens 150 could include materials such as glass (silica),polycarbonate, polyethylene, fluoride, chalcogenides, and/or otheroptical materials. In yet other embodiments, the at least one spacer 140need not be an optical material at all. In such scenarios, the at leastone spacer 140 could be formed from silicon, ceramic, or anotheroptically opaque material.

In various embodiments, the first substrate 110 could include one ormore spring structures 160 on the first surface 112 of the firstsubstrate 110. The spring structures 160 could provide a compliant,spring-like force in a direction normal to the surface of the firstsubstrate 110. In some cases, the plurality of spring structures 160could include a plurality of looped wire bonds. Other types of springsand/or spring-like structures are contemplated herein.

In example embodiments, the first substrate 110 and the second substrate130 are coupled together such that: a) at least one light-emitter deviceof the plurality of light-emitter devices 120 is in physical contactwith the at least one spacer 140; and b) at least one spring structureof the plurality of spring structures 160 is in physical contact withthe at least one cylindrical lens 150.

In some embodiments, the optical system 100 could also include a drivercircuit. The driver circuit is operable to cause the one or morelight-emitter devices 120 to emit light. In such scenarios, at least aportion of the driver circuit could be disposed on the bridge structure.

FIGS. 2A-2C illustrate various portions of an optical system, whichcould be similar or identical to optical system 100 as illustrated anddescribed in reference to FIG. 1. FIG. 2A illustrates a portion 200 ofan optical system, according to an example embodiment. Specifically,FIG. 2A shows various views of a bridge structure 102. The bridgestructure 102 includes a first surface 112, a first support end 116, anda second support end 118. The bridge structure 102 includes an elongatemember 113 that extends between the two support ends 116 and 118.Further, the elongate member 113 has a longitudinal axis 115.Additionally, two or more light-emitter devices 120 could be coupled tothe elongate member 113 along the first surface 112 of the bridgestructure 102. In some embodiments, the two or more light-emitterdevices 120 could be disposed symmetrically about the longitudinal axis115. As an example, two light-emitter devices 120 could be disposed atan equal distance from the longitudinal axis 115 along the first surface112 of the bridge structure 102.

As illustrated in the oblique view of FIG. 2A, the bridge structure 102and the elongate member 113 could be configured to bend according to atransverse mode with respect to the longitudinal axis (e.g., along atransverse axis 117 that is perpendicular to the longitudinal axis 115and perpendicular to the first surface 112). Additionally, the bridgestructure 102 could be configured to bend according to a torsional modewith respect to the longitudinal axis (e.g., in a twisting path 119about the longitudinal axis 115). Other bending modes are possible andcontemplated within the context of this disclosure.

FIG. 2B illustrates various views of a portion 210 of an optical system,according to an example embodiment. Specifically, the optical systemcould include a plurality of bridge structures 102 a, 102 b, and 102 cthat have, for example, a corresponding plurality of elongate members113 a, 113 b, and 113 c. As illustrated, the elongate members 113 a, 113b, and 113 c could be defined by cutouts 111 a and 111 b. In an exampleembodiment, cutouts 111 a and 111 b could include through-holes in thefirst substrate 110 that physically define the elongate members withrespect to one another. Although FIG. 2B illustrates N−1 cutouts for Nelongate members, it will be understood that a different relationshipbetween the number of cutouts and number of elongate members could beutilized.

As shown, a pair of light-emitter devices 120 a, 120 b, and 120 c couldbe coupled to the first surface 112 of each elongate member. In such anexample, the elongate members 113 a, 113 b, and 113 c could beconfigured to bend with respect to their respective longitudinal axes115 a, 115 b, and 115 c (e.g., according to torsional and/or transversemodes). In such a manner, minor variations in height, placement, and/orother non-uniformities could be compensated, at least in part, toprovide better alignment between the plurality of light-emitter devices120 a, 120 b, and 120 c and other optical elements (e.g., thecylindrical lens 150 and/or the structure 136) in the optical system100.

FIG. 2C illustrates an oblique view of the portion 210 of the opticalsystem, according to an example embodiment. As illustrated in FIGS. 2Band 2C, the plurality of elongate members 113 a, 113 b, and 113 c couldinclude undercut regions such that could include a reduced thickness forat least a portion of the bridge structures 102 a, 102 b, and 102 c.However, some embodiments need not include an undercut region.

FIG. 2D illustrates a side view and close-up side view of optical system230, according to an example embodiment. Optical system 230 could besimilar or identical to optical system 100, as illustrated and describedin reference to FIG. 1. For example, optical system 230 includes a firstsubstrate 110 and a second substrate 130. A plurality of light-emitterdevices 120 are coupled to a bridge structure 102 along a first surface112 of the first substrate 110. While FIG. 2D illustrates a singlelight-emitter device 120, in some embodiments, the light-emitter device120 could include a plurality of light-emitter devices (e.g., 256 ormore laser bars). In an example embodiment, the plurality oflight-emitter devices could extend “into the page” along the y-axis.

In some embodiments, a plurality of spring structures 160 could becoupled to the first surface 112 of the first substrate 110. While FIG.2D illustrates a single spring structure 160, in some embodiments, theoptical system 230 could include a plurality of spring structures (e.g.,10, 50, 100, or more spring structures). In an example embodiment, theplurality of spring structures 160 could extend “into the page” alongthe y-axis.

The second substrate 130 has a mounting surface 132 upon which ismounted a spacer 140, a cylindrical lens 150, a structure 136, and anoptical spacer 137. In an example embodiment, the cylindrical lens 150could be disposed along the mounting surface 132 and between the spacer140 and the structure 136. The spacer 140 and the cylindrical lens 150could be cylindrically-shaped and extend along the y-axis as illustratedin FIG. 2D. However, other shapes and arrangements of the spacer 140,cylindrical lens 150, structure 136, and optical spacer 137 are possibleand contemplated. In some embodiments, the second substrate 130 could bepartially transparent. As an example, the second substrate 130 could beglass or another material that is substantially optically-transparent inthe visible wavelengths and/or the wavelengths of light emitted by thelight-emitter devices.

As illustrated in FIG. 2D, the first substrate 110 is directly coupledto the second substrate 130 at least at two locations: 1) a firstportion (e.g., a portion adjacent to or including support end 116) ofthe first substrate 110 could be coupled to the mounting surface 132 ofthe second substrate 130; and 2) a second portion (e.g., a portionadjacent to or including support end 118) of the first substrate 110could be coupled to the optical spacer 137 on the second substrate 130.In such a scenario, the first surface 112 of bridge structure 102 facesthe mounting surface 132.

In some embodiments, coupling the first substrate 110 to the secondsubstrate 130 could include bonding the two substrates using an epoxy oranother optical adhesive material. Coupling the first substrate 110 andthe second substrate 130 as illustrated in FIG. 2D could cause a topsurface 222 of the at least one light-emitter device 120 to physicallycontact the spacer 140. As such, the spacer 140 could be configured toact as a “land” or stop for the light-emitter device 120 in thez-direction. That is, the spacer 140 could control the z-height of thelight-emitter device 120 when the first substrate 110 is coupled to thesecond substrate 130.

As an example, the bridge structure 102 could bend with respect to itslongitudinal axis so as to balance the forces. In other words, thebridge structure 102 could bend according to a transverse and/ortorsional mode with respect to the longitudinal axis.

The light-emitter device 120 could include an epitaxially-grown laserdiode region 224. The laser diode region 224 could include semiconductormaterial from which photons are emitted with a particular emissionpattern. By controlling the z-height of the light-emitter device 120,the location of the emission pattern 226 of the epitaxially-grown laserdiode region 224 can be positioned so as to interact with thecylindrical lens 150. That is, by moving either the light-emitter device120 or the cylindrical lens 150, their relative position can be adjustedwith respect to one another. Additionally or alternatively, a diameterof the cylindrical lens 150 could be varied (e.g., by selecting adifferent diameter optical fiber) to obtain a desired focus.

Additionally, coupling the first substrate 110 to the second substrate130 could cause a spring structure 160 to physically contact thecylindrical lens 150. That is, at least a portion of the springstructure 160 could push downward (in the −z direction) onto an outersurface of the cylindrical lens 150. In so doing, the spring structure160 could help retain and/or position the cylindrical lens 150 at adesired location.

III. Example Methods

FIGS. 3A-3G illustrate various steps of a method of manufacture,according to one or more example embodiments. It will be understood thatat least some of the various steps may be carried out in a differentorder than of that presented herein. Furthermore, steps may be added,subtracted, transposed, and/or repeated. FIGS. 3A-3G may serve asexample illustrations for at least some of the steps or blocks describedin relation to method 400 as illustrated and described in relation toFIG. 4. Additionally, some steps of FIGS. 3A-3G may be carried out so asto provide optical system 100, as illustrated and described in referenceto FIGS. 1 and 2D.

FIG. 3A illustrates a step of a method of manufacture 300, according toan example embodiment. Step 300 includes providing a first substrate110. As illustrated, a first substrate 110 could include a first surface112. The first substrate 110 could be shaped to form at least one bridgestructure 102. The bridge structure 102 could include an elongate member113 extending between a first support end 116 and a second support end118. In some embodiments, the elongate member 113 could be formed byremoving at least a portion of the first substrate 110 using methodssuch as laser cutting, mechanical routing, and/or dry or wet etchingprocesses. In some examples, the elongate member 113 could be defined bycutouts in the first surface 112 (e.g., in the x-y plane). Additionallyor alternatively, the elongate member 113 could be defined by anundercut portion in which a backside portion of the first substrate 110is partially or completely removed. The bridge structure(s) 102 couldadditionally or alternatively be formed using additive techniques (3Dprinting, etc.).

One or more light-emitter devices 120 could be disposed on the firstsurface 112. While FIG. 3A illustrates a single light-emitter device120, it will be understood that further light-emitter devices could beprovided along the “into the page” direction (e.g., extending along they-axis). In some embodiments, an epitaxially-grown laser diode region224 could be located a known distance below a top surface 222 of thelight-emitter devices 120. A plurality of spring structures 160 could beplaced on the first surface 112. For example, the spring structures 160could include wire bonds applied to the first surface 112 using a wirebonder.

FIG. 3B illustrates a step of a method of manufacture 310, according toan example embodiment. Step 310 includes providing a second substrate130. The second substrate 130 includes a mounting surface 132 and abackside surface 234. In some embodiments, the second substrate 130 maybe partially or completely transparent. For instance, the secondsubstrate 130 could be formed from glass or another material that issubstantially transparent to visible light and/or the wavelengths oflight emitted by the light-emitter devices.

FIG. 3C illustrates a step of a method of manufacture 320, according toan example embodiment. Step 320 includes forming a structure 136 andoptical spacer 137 on the mounting surface 132. In some embodiments,forming the structure 136 could include one or more photolithographyexposures to define a photo-definable resist material. In someembodiments, the structure 136 could be an optical waveguide configuredto guide light via, e.g., total internal reflection. As describedherein, the optical spacer 137 could be formed from stainless steel orother materials with similar properties.

FIG. 3D illustrates a step of a method of manufacture 330, according toan example embodiment. Step 330 includes coupling a spacer 140 to themounting surface 132 of the second substrate 130. In some embodiments,coupling the spacer 140 to the mounting surface 132 could include usinga pick-and-place system to position the spacer 140 in a desired locationalong the mounting surface 132. Additionally or alternatively, thespacer 140 could be coupled to the mounting surface 132 using epoxy oranother adhesive material.

In some embodiments, three-dimensional alignment structures 142 could beapplied to the mounting surface before or after the spacer 140 ispositioned along the mounting surface 132. The alignment structures 142could help to properly position the spacer 140 and/or help maintain itsposition. In some cases, the alignment structures 142 could bepositioned to form a slot for the spacer 140. In other words, thealignment structures 142 could grip the spacer 140 so as to affix orfasten it in place. The alignment structures 142 could be defined usingphotolithography. For example, the alignment structures 142 could beformed with a photo-definable material.

FIG. 3E illustrates a step of a method of manufacture 340, according toan example embodiment. Step 340 includes coupling a cylindrical lens 150to the mounting surface 132 of the second substrate 130. In someembodiments, coupling the cylindrical lens 150 to the mounting surface132 could include using a pick-and-place system to position thecylindrical lens 150 in a desired location along the mounting surface132. Additionally or alternatively, the cylindrical lens 150 could becoupled to the mounting surface 132 using epoxy or another adhesivematerial.

In some embodiments, three-dimensional alignment structures 152 could beapplied to the mounting surface before or after the cylindrical lens 150is positioned along the mounting surface 132. The alignment structures152 could help to properly position the cylindrical lens 150 and/or helpmaintain its position. In some cases, the alignment structures 152 couldbe positioned to form a slot for the cylindrical lens 150. In otherwords, the alignment structures 152 could grip the cylindrical lens 150so as to affix or fasten it in place. The alignment structures 152 couldbe defined using photolithography. For example, the alignment structures152 could be formed with a photo-definable material.

FIG. 3F illustrates a step of a method of manufacture 350, according toan example embodiment. Step 350 includes the first substrate 110 beingcoupled to the second substrate 130. For example, the first support end116 of the bridge structure 102 could be coupled to the mounting surface132 of the second substrate 130 and the second support end 118 of thebridge structure 102 could be coupled to the optical spacer 137. In sodoing, the first surface 112 of the first substrate 110 faces themounting surface 132.

When coupling the first substrate 110 to the second substrate 130, theone or more light-emitter devices 120 could come into physical contactwith the spacer 140. That is, a respective top surface 222 of theplurality of light-emitter devices 120 could push against the spacer140. Furthermore, as a result of coupling the first substrate 110 andthe second substrate 130, the cylindrical lens 150 could come intophysical contact with the spring structures 160. In some embodiments,the spring structures 160 may bend so as to compliantly provide a forceto a surface of the cylindrical lens 150.

In this arrangement, an epitaxially-grown laser diode region 224 couldbe uniformly and more-reliably positioned with respect to thecylindrical lens 150 such that the laser diode region 224 emits lightthat is fast-axis collimated by the cylindrical lens 150.

In some embodiments, the first substrate 110 may bend due to one or morephysical forces exerted upon it. For example, the first surface 112 andthe second surface 114 could be bent with respect to a pre-couplingcondition of the first substrate 110. That is, prior to coupling thefirst substrate 110 to the second substrate 130, the first substrate 110may be substantially planar. However, after coupling the first substrate110 to the second substrate 130, at least a portion of the firstsubstrate 110 may bend to balance the forces exerted upon the topsurface 222 of the light-emitter device 120 by the spacer 140 and/or theforces exerted upon the cylindrical lens 150 by the spring structure160, and vice versa.

More specifically, the bridge structure 102 could bend and/or flex dueto the forces. For example, the bridge structure 102 could twist about alongitudinal axis of the elongate member 113 so as to accommodatevarious heights of the light-emitter devices 120. Additionally oralternatively, the bridge structure 102 could bend away from themounting surface 132 due to the physical forces applied when couplingthe first substrate 110 to the second substrate 130.

In some examples, the first substrate 110 and/or the bridge structure102 may be “pre-bent” prior to coupling it with the second substrate130. In such a scenario, the first substrate 110 and/or the bridgestructure 102 could be plastically deformed with heat and/or pressure soas to more compliantly couple with the second substrate 130. Forexample, the first clamped end 116 of the first substrate 110 and thesecond clamped end 118 of the first substrate 110 could be pre-bent soas to reduce delamination issues after coupling with the secondsubstrate 130. Other “pre-bending” steps are contemplated so as toreduce or eliminate physical stresses on the first substrate 110, thebridge structure 102, the second substrate 130, and/or other componentsof the optical system 100.

FIG. 3G illustrates a step of a method of manufacture 360, according toan example embodiment. Step 360 could include causing the one or morelight-emitter devices 120 to emit light according to an emission pattern362. At least a portion of the emission pattern 362 could interact withthe cylindrical lens 150 to form focused light 364. In such a scenario,the focused light 364 could be coupled into the structure 136 and bepropagated within the structure 136 along the x-direction as guidedlight 366. The guided light 366 could be imaged elsewhere in the opticalsystem using, for example, one or more photodetectors (e.g., a camera).Step 360 could be utilized, for example, as a calibration step duringmanufacturing or periodically during normal operation to check properalignment of the components of the optical system 100.

FIG. 4 illustrates a method 400, according to an example embodiment.Method 400 could represent a process flow for a method of manufactureand may be carried out, at least in part, by way of some or all of themanufacturing steps or stages illustrated and described in reference toFIGS. 3A-3G. It will be understood that the method 400 may include feweror more steps or blocks than those expressly disclosed herein.Furthermore, respective steps or blocks of method 400 may be performedin any order and each step or block may be performed one or more times.In some embodiments, method 400 and its steps or blocks may be performedto provide an optical system that could be similar or identical tooptical system 100, as illustrated and described in reference to FIGS. 1and 2A-2D.

Block 402 includes forming at least one bridge structure in a firstsubstrate that has a first surface. In some examples, the firstsubstrate could include a printed circuit board. However, othermaterials are contemplated.

In some embodiments, forming at least one bridge structure in the firstsubstrate could include lithographically-defining at least one cutout inthe first substrate. The at least one cutout could include an opening inthe first substrate. For example, the bridge structure could be definedby two cutouts. In such scenarios, the bridge structure could include anelongate member and two clamped ends.

Furthermore, in some embodiments, forming at least one bridge structurein the first substrate could include forming a plurality of bridgestructures defined by a plurality of cutouts.

Block 404 includes attaching one or more light-emitter devices to thefirst surface of the bridge structure. In some embodiments, method 400could include using a pick-and-place system to position thelight-emitter devices on the first surface. In some scenarios, thelight-emitter devices could be bonded to the first surface with epoxy,an indium eutectic material, or another type of adhesive material.

Block 406 includes providing a second substrate that has a mountingsurface that defines a reference plane. The second substrate couldinclude at least one portion that is transparent so as to provide analignment window for aligning the second substrate with the firstsubstrate as described below.

Block 408 includes forming a structure and an optical spacer on themounting surface of the second substrate. In some embodiments, formingthe structure on the mounting surface of the second substrate comprisesperforming a photolithographic process to define the structure with aphotolithographically-definable material. In some embodiments, thestructure could include an optical waveguide that could be formed fromSU-8 or another optical material. As described elsewhere herein, theoptical spacer could be formed from stainless steel and could provide ascaffolding to maintain an air gap around the structure.

Block 410 includes coupling at least one spacer to the mounting surfaceof the second substrate. In some embodiments, coupling the at least onespacer to the mounting surface could include using a pick-and-placemachine to position the at least one spacer in the desired location onthe second substrate. As described elsewhere herein, the at least onespacer could include an optical fiber. However, other materials andshapes are possible and contemplated.

In some embodiments, coupling the at least one spacer to the mountingsurface of the second substrate could include coupling the at least onespacer to a plurality of three-dimensional alignment structures on themounting surface of the second substrate.

Block 412 includes coupling the first and second substrates togethersuch that a first portion of the first substrate is coupled to themounting surface of the second substrate and a second portion of thefirst substrate is coupled to the optical spacer formed on the mountingsurface of the second substrate and the first surface of the firstsubstrate faces the mounting surface of the second substrate at an anglewith respect to the reference plane. In such scenarios, the at least onespacer is in physical contact with the one or more light-emitterdevices.

In some embodiments, the structure formed on the mounting surface of thesecond substrate could be an optical waveguide. In such scenarios,coupling the first and second substrates together could includeoptically coupling at least one light-emitter device of the plurality oflight-emitter devices to the optical waveguide via the at least onecylindrical lens.

In example embodiments, coupling the first and second substratestogether includes bringing the one or more light-emitter devices intophysical contact with the at least one spacer.

Method 400 could additionally include coupling at least one cylindricallens to the mounting surface of the second substrate. In such scenarios,the one or more light-emitter devices could be disposed along an opticalaxis toward the at least one cylindrical lens. In some embodiments,coupling the at least one cylindrical lens to the mounting surface ofthe second substrate could include coupling the at least one cylindricallens to a plurality of three-dimensional alignment structures on themounting surface of the second substrate.

In some embodiments, method 400 may additionally include aligning thefirst substrate and the second substrate with respect to one anotherbefore coupling the first and second substrates together. In suchscenarios, coupling the first and second substrates together couldinclude applying an adhesive material to one or both of the first andthe second substrate and applying a predetermined contact force (e.g.,1-100 N, or more).

Method 400 could additionally include electrically-connecting thelight-emitter devices to control circuitry (e.g., pulser circuits),which could be located on the bridge structure(s) or elsewhere. Forexample, electrically-connecting the light-emitter devices to theirrespective control circuits could include forming one or more wire bondsbetween them using a wire or ribbon bonder system.

Method 400 could include forming a plurality of spring structures on thefirst surface of the first substrate. In such scenarios, coupling thefirst and second substrates together could include bringing at least onespring structure of the plurality of spring structures into physicalcontact with the at least one cylindrical lens. In some cases, theplurality of spring structures could include a plurality of looped wirebonds. That is, method 400 could include the step of applying theplurality of looped wire bonds to the first surface of the firstsubstrate (e.g., with a wire bonding system).

In some embodiments, coupling the first and second substrates togethercould include applying an adhesive material to at least one of the firstportion of the first substrate or the mounting surface of the secondsubstrate. In such scenarios, the method 400 could include applying theadhesive material to at least one of the second portion of the firstsubstrate or the optical spacer formed on the mounting surface of thesecond substrate. Furthermore, method 400 could include curing theadhesive material such that the first portion of the first substrate isbonded to the mounting surface of the second substrate and the secondportion of the first substrate is bonded to the optical spacer formed onthe mounting surface of the second substrate.

Method 400 may include aligning the first substrate and the secondsubstrate with respect to one another before coupling the first andsecond substrates together. For instance, in some embodiments where thesecond substrate includes a transparent portion, aligning the firstsubstrate and the second substrate with respect to one another couldinclude imaging at least a portion of the first substrate through thetransparent portion of the second substrate. Furthermore, in suchscenarios, aligning the first substrate and the second substrate withrespect to one another may include adjusting a position of the firstsubstrate with respect to the second substrate to achieve a desiredalignment of the first and second substrates.

Additionally or optionally, coupling the first and second substratestogether could include applying a predetermined force (e.g., between 1Newton to 100 Newtons) to the second surface of the first substrate.Other values of force are contemplated and possible.

The particular arrangements shown in the Figures should not be viewed aslimiting. It should be understood that other embodiments may includemore or less of each element shown in a given Figure. Further, some ofthe illustrated elements may be combined or omitted. Yet further, anillustrative embodiment may include elements that are not illustrated inthe Figures.

A step or block that represents a processing of information cancorrespond to circuitry that can be configured to perform the specificlogical functions of a herein-described method or technique.Alternatively or additionally, a step or block that represents aprocessing of information can correspond to a module, a segment, aphysical computer (e.g., a field programmable gate array (FPGA) orapplication-specific integrated circuit (ASIC)), or a portion of programcode (including related data). The program code can include one or moreinstructions executable by a processor for implementing specific logicalfunctions or actions in the method or technique. The program code and/orrelated data can be stored on any type of computer readable medium suchas a storage device including a disk, hard drive, or other storagemedium.

The computer readable medium can also include non-transitory computerreadable media such as computer-readable media that store data for shortperiods of time like register memory, processor cache, and random accessmemory (RAM). The computer readable media can also includenon-transitory computer readable media that store program code and/ordata for longer periods of time. Thus, the computer readable media mayinclude secondary or persistent long term storage, like read only memory(ROM), optical or magnetic disks, compact-disc read only memory(CD-ROM), for example. The computer readable media can also be any othervolatile or non-volatile storage systems. A computer readable medium canbe considered a computer readable storage medium, for example, or atangible storage device.

While various examples and embodiments have been disclosed, otherexamples and embodiments will be apparent to those skilled in the art.The various disclosed examples and embodiments are for purposes ofillustration and are not intended to be limiting, with the true scopebeing indicated by the following claims.

What is claimed is:
 1. An optical system, comprising: a first substrate,wherein the first substrate comprises at least one bridge structure,wherein the bridge structure comprises a first surface, and wherein oneor more light-emitter devices are disposed on the first surface; asecond substrate, wherein the second substrate has a mounting surfacethat defines a reference plane, wherein the second substrate comprises astructure and an optical spacer on the mounting surface; and at leastone spacer coupled to the mounting surface, wherein the first substrateand the second substrate are coupled together such that a first portionof the first substrate is coupled to the optical spacer on the mountingsurface of the second substrate and the first surface of the firstsubstrate faces the mounting surface of the second substrate at an anglewith respect to the reference plane, and wherein the at least one spaceris in physical contact with the one or more light-emitter devices. 2.The optical system of claim 1, wherein the first substrate comprises aprinted circuit board.
 3. The optical system of claim 1, wherein thebridge structure is defined by at least one cutout, wherein the at leastone cutout comprises an opening in the first substrate.
 4. The opticalsystem of claim 3, wherein the bridge structure is defined by twocutouts, wherein the bridge structure comprises an elongate memberextending between a first support end and a second support end.
 5. Theoptical system of claim 4, wherein the first and second support endsdefine a plane and the elongate member is deformable with respect to theplane.
 6. The optical system of claim 3, comprising a plurality ofbridge structures defined by a plurality of cutouts.
 7. The opticalsystem of claim 1, wherein the bridge structure comprises a longitudinalaxis, wherein the bridge structure is configured to bend according to atransverse mode with respect to the longitudinal axis.
 8. The opticalsystem of claim 1, wherein the bridge structure comprises a longitudinalaxis, wherein the bridge structure is configured to bend according to atorsional mode with respect to the longitudinal axis.
 9. The opticalsystem of claim 1, wherein the structure on the mounting surfacecomprises an optical waveguide.
 10. The optical system of claim 1,wherein the at least one spacer comprises an optical fiber spacer. 11.The optical system of claim 10, further comprising at least onecylindrical lens coupled to the mounting surface, wherein the at leastone cylindrical lens comprises an optical fiber lens having a radiusgreater than that of the optical fiber spacer.
 12. The optical system ofclaim 1, further comprising at least one cylindrical lens coupled to themounting surface, wherein the one or more light-emitter devices arearranged to emit light towards the at least one cylindrical lens. 13.The optical system of claim 1, further comprising a driver circuit,wherein the driver circuit is operable to cause the one or morelight-emitter devices to emit light.
 14. The optical system of claim 13,wherein at least a portion of the driver circuit is disposed on thebridge structure.
 15. A method of manufacturing an optical system, themethod comprising: forming at least one bridge structure in a firstsubstrate, wherein the bridge structure comprises a first surface;attaching one or more light-emitter devices to the first surface of thebridge structure; providing a second substrate, wherein the secondsubstrate has a mounting surface that defines a reference plane; forminga structure and an optical spacer on the mounting surface of the secondsubstrate; coupling at least one spacer to the mounting surface of thesecond substrate; and coupling the first and second substrates togethersuch that a first portion of the first substrate is coupled to themounting surface of the second substrate and a second portion of thefirst substrate is coupled to the optical spacer formed on the mountingsurface of the second substrate and the first surface of the firstsubstrate faces the mounting surface of the second substrate at an anglewith respect to the reference plane, wherein the at least one spacer isin physical contact with the one or more light-emitter devices.
 16. Themethod of claim 15, wherein forming at least one bridge structure in thefirst substrate comprises lithographically-defining at least one cutoutin the first substrate, wherein the at least one cutout comprises anopening in the first substrate.
 17. The method of claim 16, wherein thebridge structure is defined by two cutouts, wherein the bridge structurecomprises an elongate member and two clamped ends.
 18. The method ofclaim 16, wherein forming at least one bridge structure in the firstsubstrate comprises forming a plurality of bridge structures defined bya plurality of cutouts.
 19. The method of claim 15, further comprisingcoupling at least one cylindrical lens to the mounting surface of thesecond substrate, wherein the one or more light-emitter devices aredisposed along an optical axis toward the at least one cylindrical lens.20. The method of claim 15, further comprising: aligning the firstsubstrate and the second substrate with respect to one another beforecoupling the first and second substrates together, wherein coupling thefirst and second substrates together comprises: applying an adhesivematerial to one or both of the first and the second substrate; andapplying a predetermined contact force.